The invention relates to a drying balance with a radiation source for heating and drying a substance distributed on a balance scale, with a temperature sensor for monitoring and controlling the output of the radiation source and with electronic evaluating circuitry for evaluating the measured results of the balance and for controlling the drying balance.
Drying balances of this type are generally known, e.g. from the generic patent DE-GM No. 86 06 298. The geometric design of such a drying balance is shown e.g. in DE-OS No. 36 15 660.
However, the known drying balances have the disadvantage that the temperature sensor does not directly measure the temperature of the substance to be dried but rather is located only in the vicinity of the substance to be dried. A different radiation density at the location of the substance to be dried and at the location of the temperature sensor as well as, in particular, different coefficients of absorption for the radiation result in a temperature difference between the temperature sensor and the substance to be dried which varies in magnitude as a characteristic of the substance.
The invention therefore provides the solution of creating the means of measuring this temperature difference and of taking it into consideration when controlling the output of the radiation source.